stylelint/src/rules/selector-list-comma-space-after/index.js

Modern CSS linter

import {
  report,
  ruleMessages,
  styleSearch,
  validateOptions,
  whitespaceChecker,
} from "../../utils"

export const ruleName = "selector-list-comma-space-after"

export const messages = ruleMessages(ruleName, {
  expectedAfter: () => "Expected single space after \",\"",
  rejectedAfter: () => "Unexpected whitespace after \",\"",
  expectedAfterSingleLine: () => "Expected single space after \",\" in a single-line list",
  rejectedAfterSingleLine: () => "Unexpected whitespace after \",\" in a single-line list",
})

export default function (expectation) {
  const checker = whitespaceChecker("space", expectation, messages)
  return (root, result) => {
    const validOptions = validateOptions(result, ruleName, {
      actual: expectation,
      possible: [
        "always",
        "never",
        "always-single-line",
        "never-single-line",
      ],
    })
    if (!validOptions) { return }

    selectorListCommaWhitespaceChecker({
      root,
      result,
      locationChecker: checker.after,
      checkedRuleName: ruleName,
    })
  }
}

export function selectorListCommaWhitespaceChecker({ locationChecker, root, result, checkedRuleName }) {
  root.walkRules(rule => {
    const selector = rule.selector
    styleSearch({ source: selector, target: ",", outsideFunctionalNotation: true }, match => {
      checkDelimiter(selector, match.startIndex, rule)
    })
  })

  function checkDelimiter(source, index, node) {
    locationChecker({ source, index, err: m =>
      report({
        message: m,
        node,
        index,
        result,
        ruleName: checkedRuleName,
      }),
    })
  }
}